Vortex burner



Nov. 4, 1969 w. 1.. BUCHANAN ET VORTEX BURNER 3 SheetsSheet l Filed Aug. 29, 1967 xm/v S w R Y mm m m a m n l/h. #5 y M 4 Nov. 4, 1969 w. L. BUCHANAN ET AL 3,476,494

VORTEX BURNER Filed Aug. 29, 1967 s Sheets-Sheet 2 T'lq.2.

ATTORNEY Nov. 4, 1969 w. L. BUCHANAN ET AL 3,476,494

VORTEX BURNER Filed Aug. 29, 1967 3 Sheets-Sheet 5 EBY F ATTOR EY Patented Nov. 4, 1969 3,476,494 VORTEX BURNER William L. Buchanan, Sparta, and Harry F. Straight, Jr., Succasunna, N.J., asssignors to Esso Research and Engineering Company, a corporation of Delaware Filed Aug. 29, 1967, Ser. No. 664,170 Int. Cl. F23d 13/40; F23m 9/00 U.S. Cl. 431-353 8 Claims ABSTRACT OF THE DISCLOSURE Background of the invention In general the present invention relates to an improved swirl or vortex type burner which produces blue flame or flameless type combustion with a minimum of excess arr.

In particular the present invention relates to an improved burner construction yielding increased heat release per unit volume of combustion space and having a high degree of stability producing a minimum of pulsation noise. The invention further relates to an improved swirl air inlet or induction chamber design configuration which produces a maximum vortex eflect with a minimum of pressure drop.

In accordance with the present invention a ceramic lined cylindrical combustion chamber is provided with an air induction chamber at one end thereof for the introduction of swirling air and a fluid fuel mixture. The air induction chamber is of substantially uniform cylindrical diameter corresponding in diameter to the inlet orifice to the combustion chamber and is provided with a plurality of tangential nozzles about its periphery. Air, under pressure, is forced into the air induction chamber surrounding these tangential nozzles and tangentially enters the swirl sleeve to create an internal air vortex. Upon movement of the vortex into the combustion chamber, its expansion into the larger diameter of the combustion chamber is regulated by the provision of an angular fillet at the base of the combustion chamber. The included angle of the fillet is substantially the same as the divergent angle of the fuel spray emitted from the fuel nozzle lying essentially in the plane of the inlet to the combustion chamber. In this way the flame stability is increased and the swirling motion of the air entering the combustion chamber is prolonged. Furthermore, the presence of the fillet at this critical area of the combustion chamber provides a heated surface for assisting the vaporization of the fuel. The injection of fuel into the combustion chamber at a divergent angle corresponding to the angle of divergence of the fillet places the fuel at a point where it can burn immediately to produce an optimum blue flame condition. This aspect of creating an environment of optimum combustion in applicants arrangement has produced a burner of exceedingly high heat release per unit volume of combustion space wherein the flame is highly stable and therefore produces a minimum of noise. Noise abatement is of considerable importance in burners having a capacity in the order of 50 million B.t.u.s heat release per hour.

Accordingly, it is the principal object of the invention to produce a new and improved burner for fluid fuel.

Another object of the invention is to provide a vortex burner having an air induction system presenting a minimum of pressure drop to the forced air input supplied thereto.

Another object of the invention is to provide a combustion device which is highly reliable, economic to manufacture, simple in design, and low in noise level.

These and other objects and advantages of the invention will become apparent and the invention will be fully understood from the following description and drawings in which:

FIG. 1 is a view, partially in section of one embodiment of the invention, taken along the line 1--1 of FIG. 2;

FIG. 2 is an end view, partially in section, taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view of the invention taken along line 3-3 of FIG. 1;

FIG. 4 is an end view of the air induction chamber taken along line 4-4 of FIG. 3;

FIG. 5 is a perspective view of one form of air inlet sleeve employed in the invention;

FIG. 6 is a view similar to FIG. 1 showing a modified form of the invention; and

FIG. 7 is a perspective view similar to FIG. 5 showing another form of air inlet sleeve.

Referring to the drawings in particular, a burner shown generally at 10 is mounted in a typical furnace wall 12 by an annular flange 20. A thin layer of asbestos packing 22 is employed to seal the gap between the aperture in the furnace wall and the outside diameter of the burner 10. The furnace, of which the wall 12 forms merely a portion, will be presumed to include a firebox area designated 14. The burner 10 includes a combustion chamber portion 16 surrounded by a metallic outer shell 18. The interior of the combustion chamber formed by the outer shell 18 includes a plurality of layers 24 of refractory heat insulation material. The innermost refractory layer 24 includes an annular fillet or conical bottom portion 26 surrounding the air and fuel inlet opening 27 at the base of the combustion chamber 16.

The air and fuel inlet end 30 of the burner 10 includes an end plate 32 affixed by conventional means to a flange 34 of the outer shell 18. An air swirl nozzle chamber or sleeve 38 is attached to the interior surface of the end plate 32 by a weld 42. The air swirl sleeve 38 extends from the plate 32 across and through an air inlet plenum chamber 36 into the inlet opening 27 of the combustion chamber and terminates adjacent the conical fillet 26. The open end of the inner swirl sleeve 38 is supported in the combustion chamber opening 27 by a ring of suitable packing ring 28 which may be made of asbestos or other similar material.

Referring in more detail to FIGS. 2, 4, and 5, the

structural features of the air swirl nozzle sleeve 38 may be readily appreciated. The sleeve 38 includes a plurality of tangential inlet nozzles 40 which receive air under pressure from a suitable blower means (not shown) communicating with the air inlet flange 41. The combustion air flowing through the nozzles 40 has imparted thereto a swirling or vortex movement about the interior Walls of the sleeve 38 and subsequently expands into the inlet end of the combustion chamber. The interior of the sleeve 38 includes a fuel nozzle support tube 44 having a plurality of set screws 46 spaced thereabout and exterior of the end plate 32. These screws 46 are provided so that a fuel spray nozzle shown generally at 48 may be readily adjusted axially to place the plane of the outlet orifices in relation to the divergent spray angle in an optimum position relative to the angle and position of fillet 26 for most eflicient combustion. The inner end of the burner tube 44 is supported by a conical air chamber cone 50 which includes a plurality of apertures 52 therethrough. The cone 50 effectively supports the inner end of the tube 44 and at the same time prohibits the hot products of combustion from recirculating propagation of the flame in the combustion chamber rearwardly past the point of the cone to effectively protect the rear portion of the burner. Located on the exterior wall of the combustion chamber 16 is a viewing peephole 54 through which observations of the combustion chamber may be made. A similar inspection device is provided in the rear plate 32 to permit viewing the flame in an axial direction. Observation through the peephole 54 on the rear plate 32 of the flame is made through the apertures 52 in the cone 50 which are made of sufiicient diameter to permit such observation.

Each of the tangential area inlet nozzles 40 include a pair of adjacent perpendicular side walls 56, as well as a pair of convergent side walls 58, also adjacent one another. In this way a minimum pressure drop results through the inlet nozzles 40, and in combination with the substantially constant and uniform diameter of the sleeve 38 a burner is provided by the invention which has extremely low power requirements for the input air as well as high burning efiiciency due to the optimized position of the fuel spray relative to the expanding vortex of combustion air. In particular, it should be noted that the angle of the spray cone of the fuel emitted from the end of the fuel tube 48 is substantially the same as the included angle between the angular fillet 26. Preferably, these angles of the fuel spray and the cone are kept within the range of 90 to 100.

The provision of the conical bottom at this angle adds significantly to the combustion stability and shapes the fuel-air sprays and prolongs the swirling motion of the air entering the combustion chamber. In addition, the cone fillet 26 prevents an overly swirled air stream which may exit the air chamber from expanding into too big an angle which would result in poor fuel-air mixing. In other words, the provision of the fillet 26 presents an upper limit to the angle of divergence that the swirling air exiting the sleeve 38 may assume. This feature in combination with the constant diameter and small diameter of the air inlet sleeve 38 produces a new and improved burner having substantially improved combustion characteristics.

Referring to FIGS. 6 and 7, a modified form of burner is disclosed. Parts having similar functions have been given similar element designations and will not be described again. However, the burner of FIGS. 6 and 7 will be seen to include a modified air swirl chamber 60 having a plurality of non-convergent tangential nozzle 62. The cross-sectional area of nozzle 62 remains uniform. In this Way, while a slightly higher pressure drop may result than experienced in the convergent cross-section of FIGS. 4 and 5 of the first described embodiment, a higher tangential velocity is associated with this modified nozzle design. The combustion chamber 16 of the burner of FIG. 6 includes a restricted outlet orifice 68 defined by an increased and converging thickness of additional refractory material shown at 64. In this way higher exit velocities of the products of combustion are obtained than would be obtained by the unthrottled outlet orifice of the combustion chamber 16 of FIG. 1. Preferably the the diameter of the exit orifice 6 8 is less than one-half the axial length of convergent side wall portion of the combustion chamber 16, the latter portion constituting the jet forming section of the burner. This ratio of diameter to length will ensure that a well defined stable jet of combustion products is projected into the adjacent furnace heat transfer chamber 14.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A combustion device for fluid fuel comprising a refractory lined cylindrical combustion chamber, said chamber including a circular outlet at one end for discharging combustion products therefrom, and a circular inlet at the end of said chamber opposite said outlet for the introduction of fluid fuel and swirling air; and air induction means communicating with said combustion chamber circular inlet for introducing air in a helical vortex into said combustion chamber, said induction means comprising an elongated cylindrical sleeve of substantially uniform diameter throughout its length corresponding in diameter substantially to the diameter of said circular inlet; a plurality of circumferentially spaced tangential air inlet passageways extending outwardly from the outer surface of said cylindrical sleeve for admitting air tangentially in a spiral vortex to said sleeve with a maximum vortex effect and minimum pressure drop, fuel nozzle means concentric with the axis of said sleeve and having divergent outlet spray orifice means for projecting fuel into said combustion chamber; and annular conical fillet means in said combustion chamber adjacent and surrounding said circular inlet, the included angle of said fillet being substantially the same as the divergent angle of the fuel spray from said spray orifice means.

2. A combustion device in accordance with claim 1 wherein said inlet passageways are of substantially uniform rectangular cross section.

3. A combustion device in accordance with claim 1 wherein said inlet passageways are of tapering rectangular cross section.

4. A combustion device in accordance with claim 1 including an annular plate means having a plurality of apertures therethrough extending between said fuel nozzle means and said elongated cylindrical sleeve for preventing the rearward propagation of flame from the combustion chamber past said plate means.

5. A combustion device in accordance with claim 4 wherein the circular outlet of said combustion chamber is of a diameter less than the maximum diameter of said combustion chamber to thereby increase the exit velocity of the products of combustion exiting from said combustion chamber.

6. A combination device in accordance with claim 1 wherein the included angle of said fillet is substantially to 7. A combination device in accordance with claim 1 wherein a portion of the interior side walls of the combustion chamber converge inwardly to define a jet forming section terminating in said circular outlet, the diameter of said outlet being less than 50% of the axial length of said jet forming section whereby a well defined and stable jet of combustion products is produced.

8. A combustion device in accordance with claim 4 wherein said annular plate means is in the form of a truncated cone.

(References on following page) References Cited 3,118,489 1/1964 Anthes 431-158 UNITED STATES PATENTS 3,327,762 6/1967 Saha 431-183 8/1938 Woolley 15s -1.5 FOREIGN PATENTS 5/1940 Hicks 158 1 5 5 1,360,069 3/1964 France. 12/1955 Massier- EDWARD G. FAVORS, Primary Examiner 9/1957 Te Nuyl 158-4 12/1961 Huge 158-15 8/1966 Wolfersperger 1581.5 10 431--182;239406 

